I have a Blue-point 4 drawer cart, and lately, Im thinking a folding side shelf would be a great addition to it but I dont want to spend a ton of cash on this. I dont intend to store tools on it, or load it heavily,but mostly use it for carburetor rebuilds, and small things like that. What do you recommend?

The craftsman one is much cheaper, but IMHO much lighter than the SO or Mac ones.
) and a bit expensive, but really nice. For $50 using those, I would be more worried about flipping your cart over than I would be about damaging the side shelf.